app/models/spam_observer.rb

   1 class SpamObserver < ActiveRecord::Observer
   2   observe User, DiaryEntry, DiaryComment
   3
   4   def after_save(record)
   5     case
   6     when record.is_a?(User) then user = record
   7     when record.is_a?(DiaryEntry) then user = record.user
   8     when record.is_a?(DiaryComment) then user = record.user
   9     end
  10
  11     if user.status == "active" and user.spam_score > SPAM_THRESHOLD
  12       user.update_column(:status, "suspended")
  13     end
  14   end
  15 end